Cardioplegia occluder

ABSTRACT

A cardioplegia occluder and methods of using the device during cardiac surgery are disclosed. The system typically includes a substantially rigid cannula with an occluder mounted on the distal region of the cannula that expands upon activation to occlude the aorta downstream of an infusion port which delivers cardioplegia solution to arrest the heart. Systems including cutting blades, blade guards, flanges, radiopaque markers and occluder aligners are also disclosed. In use, the distal end of the cannula is inserted through an incision into the aorta, the occluder is expanded and cardioplegia solution is infused upstream of the aorta to arrest the heart. The infusion port can alternately be used to aspirate cardioplegia or embolic debris or other unwanted material from the aorta.

This is a continuation-in-part of U.S. application Ser. No. 08/854,806,filed May 12, 1997, which is a continuation-in-part of U.S. applicationSer. No. 08/645,762, filed May 14, 1996, now abandoned. The contents ofthese prior applications are expressly incorporated herein by referencein their entirety.

FIELD OF THE INVENTION

This invention relates to methods and apparatus for administeringcardioplegia to the aorta during cardiac surgery. The devices include acardioplegia occluder that can include various features such as acutting blade, a blade guard, a flange, radiopaque markers and anoccluder aligner to properly position the distal end of the devicewithin the aorta. Once the cardioplegia occluder is in its properposition, the occluder is expanded to occlude the aorta downstream ofthe infusion port and cardioplegia solution is then introduced throughthe infusion port to arrest the heart. The infusion port can alternatelybe used to aspirate cardioplegia or embolic debris or other unwantedmaterial from the aorta.

BACKGROUND

Currently, the most common method of temporarily occluding the ascendingaorta and arresting the heart during open heart surgery utilizes amechanical cross clamp and a cardioplegia cannula. Once the chest cavityhas been opened, access to the heart and to the adjacent vessels isprovided. The ascending aorta is partially dissected from thesurrounding tissue and exposed. Arterial and venous cannulas areinserted and sutured into place. The cannulas are connected to thecardiopulmonary bypass machine, and bypass blood oxygenation isestablished.

At this point, the heart must be arrested and isolated from the rest ofthe circulatory system. A mechanical cross clamp is positioned betweenthe cardioplegia cannula and the aortic cannula and is actuated. Theaorta is completely collapsed at the clamp site, thus stopping flow ofblood between the coronary arteries and the innominate artery, and theoxygenated bypass blood is shunted around the heart. Once the vesselocclusion has been completed, cardioplegia solution is introducedthrough the cardioplegia cannula to arrest the heart. The surgeon maynow proceed with the desired operation.

Other less common means of occluding the aorta include percutaneousballoon catheter occlusion, direct aortic balloon catheter (Foley)occlusion, aortic balloon catheter occlusion, and an inflating diaphragmoccluder (Hill-occlusion trocar). The percutaneous balloon catheter isinserted typically from the femoral artery feed through the descendingaorta, across the aortic arch into position in the ascending aorta. Oncein the ascending aorta, the balloon occluder is inflated and flowstopped.

As a simple replacement for the mechanical cross clamp, a Foley cathetermay be placed through an additional incision site near the standardcross clamp site. Once inserted, the Foley catheter balloon is inflatedand flow is stopped. Similarly, an aortic balloon catheter is placeddirectly into the aorta. This catheter replaces the standard aorticcannula by delivering the CPB blood back to the arterial circulatorysystem. The occluder balloon is located on the catheter proximal to CPBblood exit port on the cannula. The occlusion trocar is desired to offersimilar features as the aortic balloon occluder cannula and would beused in place of the standard aortic cannula. However, it relies on aninflatable diaphragm to occlude the vessel.

The use of a balloon to occlude an artery has been disclosed by Gabbay,U.S. Pat. No. 5,330,451 (this and all other references cited herein areexpressly incorporated by reference as if fully set forth in theirentirety herein). The Gabbay device included a perfusion cannula havinga proximal balloon occluder and a distal intra-aortic balloon to divertblood to the carotid arteries. The Gabbay perfusion cannula is disclosedfor use during open heart surgery in order to prevent complicationsassociated therewith.

Moreover, Peters, U.S. Pat. No. 5,433,700, discusses a method forinducing cardioplegic arrest using an arterial balloon catheter toocclude the ascending aorta. The Peters method includes the steps ofmaintaining systemic circulation using peripheral cardiopulmonarybypass, venting the left side of the heart, and introducing acardioplegic agent into the coronary circulation. This procedure is saidto prepare the heart for a variety of surgical procedures. Disclosuresof similar endovascular occlusion catheters can be found in Machold etal., U.S. Pat. No. 5,458,574, Stevens, International Application No.PCT/US93/12323, Stevens et al., International Application No.PCT/US94/12986, Nasu, U.S. Pat. No. 5,425,708 and Grinfeld et al., U.S.Pat. No. 5,312,344.

Each of the existing methods of blocking aortic blood flow and arrestingthe heart carries with it some undesired aspects. The mechanical crossclamp offers simplicity and reliably consistent operation. However, thephysical clamping action on the vessel has been linked to many adversebody responses. Barbut et al. ("Cerebral Emboli Detected During BypassSurgery Are Associated With Clamp Removal," Stroke, 25(12):2398-2402(1994), incorporated herein by reference in its entirety) noted themajority of embolic events (release) is associated with the actuationand release of the cross clamp during coronary bypass graph surgery. Theclamping action may be responsible for breaking up and freeingatherosclerotic buildup on the vessel walls. In addition, the potentialfor vascular damage, like aortic dissections, may also incur during theclamp application.

The percutaneous balloon catheter occluder has a distinct drawback inthat it must be placed with visionary assistance. Fluoroscopy istypically used to position the device in the aorta. This added equipmentis not always readily available in the surgical suite. In addition, thecatheter placement up to the aorta may also create additional vasculartrauma and emboli generation.

The use of a Foley catheter to occlude the aorta requires an additionalincision site to place the device. The extra cut is an additional insultsite and requires sutures to close. Generation of emboli and thepotential of aortic dissection directly associated with just theincision may potentially outweigh the benefits of using the catheter.

The aortic balloon occluder cannula addresses many of the deficienciesof the previous devices. Placement is easy to visualize, no extra cutsare required, and there is no need for the potentially traumatic crossclamp. However the currently-available aortic balloon occluders sufferfrom problems of migration within the ascending aorta because thecannulas on which the balloons are mounted are typically flexible tubesas disclosed by Grinfeld et al. and Nasu. Attempts to solve themigration problem include balloon designs with a large "footprint" inthe distal region of the cannula. (See Nasu, supra.) This largefootprint balloon is a less than adequate solution because it encroachesinto the already limited area of the ascending aorta in which surgicalaccess is available. Further, use of each of these aortic occludingballoons requires a cardioplegia cannula to be inserted through anadditional incision site to arrest the heart.

A need exists for an aortic cannula having both a balloon occluder whichcan isolate the ascending aorta from peripheral vasculature withoutsubstantial migration of the occluder into the ascending aorta, therebyreducing or eliminating the need for aortic cross-clamping, and anassociated cardioplegia infusion port which eliminates the need for aseparate incision for a cardioplegia cannula. Existing devices areinadequate for this purpose.

SUMMARY OF THE INVENTION

The present invention relates to medical devices and their methods ofuse, and particularly cardioplegia occluders. The cardioplegia occluderscomprise a cannula having an occluder to isolate the ascending aortafrom peripheral vasculature during cardiac surgery and an infusion portfor administering cardioplegia to arrest the heart. The infusion portcan alternately be used to aspirate cardioplegia or embolic debris orother unwanted material from the aorta. The devices of the presentinvention may include various features such as a cutting blade, a bladeguard, a flange, radiopaque markers and an occluder aligner to properlyposition the distal end of the device within the aorta.

In one embodiment, the device includes a substantially rigid cannulaadapted to enter the aorta with a proximal end that receivescardioplegia solution into a cardioplegia lumen and delivers it to aninfusion port in the distal region of the cannula. An occluder, mountedon the distal region of the cannula, expands away from the cannula uponactivation to substantially occlude the aorta downstream from theinfusion port. During use, the occluder isolates the ascending aortafrom the peripheral vasculature. The substantially rigid nature of thecannula inhibits migration of the occluder into the ascending aorta,thus overcoming problems associated with other currently availableaortic balloon cannulas. In certain embodiments, the occluder is aninflatable balloon. In other embodiments, the occluder is a foam-filled,self-expanding balloon. Certain balloon embodiments also include a lumenwhich can be used to inflate the balloon or alternately can be used toapply negative pressure to deflate the balloon. Other embodimentsinclude an aspiration lumen which terminates at the infusion port sothat the infusion port can alternately be used to deliver cardioplegiasolution or aspirate embolic debris and other unwanted material from theaorta. Another embodiment further includes an occluder aligner to helpposition the distal end of the cannula within the aorta and to stabilizethe position of the occluder during expansion. In another embodiment,the device includes a cannula associated with a cutting blade which isadapted to cut through the wall of the aorta to allow introduction ofthe cannula. The proximal end of the cannula is adapted to receivecardioplegia solution into a cardioplegia lumen and deliver it to aninfusion port in the distal region of the cannula. An occluder mountedon the distal region of the cannula expands away from the cannula uponactivation to substantially occlude the aorta downstream from theinfusion port. During use, the occluder isolates the ascending aortafrom the peripheral vasculature. Certain embodiments also include ablade guard which moves when pressed against the aorta to allow theblade to cut through the wall of the aorta and then repositions toprevent the blade from cutting. Other embodiments further include anoccluder aligner, a lumen which can be used to inflate the or deflatethe balloon or an aspiration lumen which terminates with the infusionport.

The methods of the present invention include administering cardioplegiato the aorta during cardiac surgery using a cardioplegia occluder asdescribed above. An incision is made in the aorta, and the distal end ofthe cannula is inserted through the incision. The occluder is expandedto occlude the aorta and thereby isolate the ascending aorta fromperipheral circulation without substantial migration of the occluderwithin the ascending aorta. Cardioplegia solution is then infusedthrough the infusion port to arrest the heart. In embodiments thatinclude a cutting blade, the step of making the incision in the aorta isperformed by the cutting blade. In embodiments that include anaspiration lumen, the method further includes the step of aspiratingcardioplegia and embolic debris from the aorta by applying negativepressure to the aspiration lumen.

BRIEF DESCRIPTION OF DRAWINGS

Reference is now made to a brief description of the drawings, which areintended to illustrate a cardioplegia occluder for use herein. Thedrawings and detailed description which follow are intended to be merelyillustrative and are not intended to limit the scope of the invention asset forth in the appended claims.

FIG. 1 depicts an embodiment of a cardioplegia occluder with a cannulahaving three lumens.

FIG. 2 depicts a lateral cross-section of the distal region of theembodiment of FIG. 1.

FIG. 3 depicts another embodiment of a cardioplegia occluder with acutting blade and a retractable blade guard.

FIG. 4 depicts a lateral cross-section of the distal region of theembodiment of FIG. 3.

FIG. 5 depicts an embodiment of a cannula with a side channel having acardioplegia occluder.

FIG. 6 shows the cardioplegia occluder inserted into the aorta via aminimally invasive chest port.

FIG. 7 depicts a lateral cross-section of an embodiment having anL-shaped cannula with infusion ports proximal to the occluder.

FIG. 7A depicts a lateral cross-section of an embodiment having anL-shaped cannula with an infusion port at the distal end of the cannula.

FIG. 8 shows a lateral view of an embodiment with a separatelyinsertable balloon cannula, a separately insertable filter cannula and aseparately insertable cutting blade.

FIG. 9 depicts a lateral cross-section of an embodiment with an angledretractable cutting blade.

FIG. 10 depicts a lateral cross-section of an embodiment with aspring-mounted retractable cutting blade and a curved distal region ofthe cannula which can serve as a blade guard.

FIG. 10A depicts a lateral cross-section of an embodiment where the endof the distal region is sharpened to form a cutting blade and the bladeguard is a retractable obturator received through the cutting blade.

FIG. 11 shows a lateral cross-section of an embodiment with a ballooncannula slidably inserted in a flange sleeve where the distal end of theflange sleeve is sharpened to form a cutting blade.

FIG. 12 shows the embodiment of FIG. 11 where the balloon cannula andthe expanded occluder have advanced beyond the distal end of the flangesleeve and into the vessel.

FIG. 13 shows lateral cross-section of an embodiment with an exposedcutting blade and a cannula with a collapsed occluder positioned insidethe flange sleeve.

FIG. 13A shows the embodiment of FIG. 13 where the cannula and theexpanded occluder have advanced beyond the end of the flange sleeve andinto the vessel, and the cutting blade is retracted inside the distalend of the cannula.

FIG. 14 depicts a lateral cross-section of an embodiment partiallyinserted into a vessel where the embodiment includes a detachableintermediate flange containing a cannula with a collapsed occluder andan exposed cutting blade.

FIG. 14A depicts the embodiment of FIG. 14 where the cannula and theexpanded occluder have advanced beyond the end of the flange and intothe vessel and the cutting blade is retracted.

FIG. 15 shows a lateral cross-section of an embodiment having flangemounted on the cannula and a steering wire coupled to the distal end ofthe cannula where the occluder is in a collapsed condition.

FIG. 15A shows the embodiment of FIG. 15 where the steering wire hasbeen manipulated to curve the distal end of the cannula and the occluderis in an expanded condition.

FIG. 16 depicts a lateral cross-section of an embodiment having flangeand a hinged distal cannula region where the hinge is in a closedcondition and the occluder is in a collapsed condition.

FIG. 16A depicts the embodiment of FIG. 16 where the hinge is in an opencondition creating an infusion port, and the occluder is in an expandedcondition.

FIG. 17 is a lateral cross-section of an embodiment having a flange witha directional indicator, a cannula with three lumens, a cutting bladeand radiopaque marker bands, where the cannula is inserted through an 18French incision.

FIG. 18 is a top elevation of the embodiment of FIG. 17 showing thealignment of the directional indicator of the flange with the distalregion of the cannula.

FIG. 19 shows a lateral elevation of an embodiment with radiopaquemarker bands and an occluder asymmetrically disposed about the distalend of the cannula.

FIG. 19A shows the embodiment of FIG. 19 where the bottom region of theasymmetrically disposed occluder is preferentially expanding whencompared to the top region.

FIG. 20 shows the front view of the embodiment of FIG. 19, showing thepreferential expansion of the bottom region of the occluder as theoccluder goes from a collapsed condition to an expanded condition.

FIG. 21 shows an embodiment of an occluder that is an asymmetricpolyurethane balloon.

FIG. 22 is a lateral view of the embodiment of FIG. 21.

FIG. 23 shows an embodiment of an asymmetric occluder that is a balloonwith a thick region and a thin region where the asymmetric configurationof the balloon is shown in a collapsed condition, and when expanded, theballoon becomes symmetric.

FIG. 24 shows an embodiment of an symmetric occluder that is a balloonwith a higher shore region and a lower shore region where the symmetricconfiguration of the balloon is shown in a collapsed condition and, whenexpanded, the balloon becomes asymmetric.

FIG. 25 depicts an embodiment where the occluder is a balloon with wallsof varying thickness.

FIG. 26 depicts an embodiment with a three-lumen cannula having a curveddistal cannula region.

FIG. 27 is a front view of the embodiment of FIG. 26.

FIG. 28 is a lateral cross-section of the embodiment of FIG. 27 shownthrough section line 28--28.

FIG. 29 is a front view of the distal region of the cannula of theembodiment of FIG. 26 showing the closed distal end.

FIG. 30 is a top elevation of the embodiment of FIG. 29.

FIG. 31 a lateral view of the embodiment of FIG. 29 with a partialcross-section.

FIG. 32 is a bottom elevation of the embodiment of FIG. 29 showing theclosed distal end.

FIG. 33 is a back elevation of the embodiment of FIG. 29.

FIG. 34 is a lateral cross-section of the embodiment of FIG. 29 shownthrough section line 34--34.

FIG. 35 is an embodiment showing a self expanding occluder with aNitinol frame, a balloon seal and an impermeable membrane.

FIG. 36 shows an embodiment of a cannula poised to receive the occluderof FIG. 35.

FIG. 37 shows the occluder of FIG. 35 inserted through the side port ofthe cannula of FIG. 36.

FIG. 38 shows an embodiment of an occluder where the balloon has excessballoon material.

FIG. 39 shows a lateral cross-section of an embodiment of an occluderwhere the balloon is stored inside the distal end of the cannula whenthe balloon is in its collapsed condition and expands out the end of thecannula.

FIG. 40 shows a lateral cross-section of an embodiment of an occluderwhere the balloon includes an elastic line that is used to pull thecollapsed balloon back into the end of the cannula.

FIG. 41 shows a lateral cross-section of an embodiment of an occluderwhere the balloon is shown in a collapsed, partially expanded and fullyexpanded condition.

FIG. 42 depicts a lateral cross-section of an embodiment of an occluderwhere the balloon is an elastic material covered by a protective layer.

FIG. 43 depicts a lateral view of an embodiment of an occluder that is afunnel-shaped balloon expanding out the side of the distal end of thecannula.

FIG. 44 depicts a lateral cross-section of an embodiment having anoccluder aligner with a spring and an end sleeve shown with the occluderin a collapsed condition.

FIG. 44A depicts the embodiment of FIG. 44 with the occluder in anexpanded condition.

FIG. 45 shows the embodiment of FIG. 44 also having a cutting blade.

FIG. 46 shows a lateral cross-section an embodiment having a steeringwire and a flexible tube occluder aligner where the occluder is in acollapsed condition.

FIG. 46A shows the embodiment of FIG. 46 in an expanded condition wherethe steering wire has been manipulated to elevate the cannula tip.

FIG. 46B is an enlarged view of the distal end of the embodiment of FIG.46A.

FIG. 47 depicts a cardioplegia occluder positioned inside the aortaupstream from a blood cannula having a side channel housing a separatelyinsertable filter cannula, both upstream from a diverter.

FIG. 47A depicts a cardioplegia occluder having a separately insertablefilter cannula positioned inside the aorta upstream from a blood cannulawhich is upstream from a diverter.

FIG. 48 depicts a cardioplegia occluder which is upstream from a filtercannula which is upstream from a blood cannula which is upstream from adiverter.

FIG. 49 depicts a cardioplegia cannula upstream from an occlusion bloodcannula with a separately insertable filter, upstream from a diverter.

FIG. 50 depicts a cardioplegia occluder which is upstream from aseparate stick filter which is upstream from a blood cannula which isupstream from a diverter.

FIG. 51 depicts a cardioplegia occluder blood cannula which is upstreamfrom a separately insertable filter which is upstream from a diverter.

DETAILED DESCRIPTION

FIG. 1 depicts an embodiment of a cardioplegia occluder 1 for deliveringcardioplegia to the aorta during cardiopulmonary bypass where the distalregion 2 of the substantially rigid cannula 3 is curved to facilitateself-centering inside the aorta. The distal end of the cannula 14 isadapted to enter the aorta In this embodiment, a spherical occluder 20is circumferentially disposed about the outer surface 15 of the distalregion of the cannula forming a chamber 21 with an inner surface 22, anouter surface, a proximal end 24 and a distal end. In some embodiments,the occluder is an inflatable balloon. In other embodiments, the balloonis foam-filled, so that the occluder may be inserted in a contractedcondition, for instance, within a sleeve or under negative pressure, andwhen released from the sleeve or the negative pressure, willautomatically expand to the predetermined shape. Although FIG. 1 andFIG. 2 depict the occluder as spherical, in other embodiments, it isconical, elliptical or funnel shaped. In the embodiment of FIG. 1 andFIG. 2, the occluder is an inflatable balloon covering a portion of thecurved distal region of the cannula. In certain embodiments, theoccluder is circumferentially disposed about the distal region of thecannula so that the cannula runs through the longitudinal center axis ofthe occluder. In other embodiments, the occluder is circumferentiallydisposed about the distal region of the cannula so that the cannula runsthrough a region displaced laterally from the longitudinal center axisof the occluder. For a detailed discussion of the construction of aballoon occluder disposed on a cannula, the reader is referred tocopending Barbut et al., U.S. application Ser. No. 08/645,762, filed May14, 1996, now abandoned, and Tsugita et al., Ser. No. 08/854,806, filedMay 12, 1997, both expressly incorporated herein by reference.

The cannula is typically a rigid or semi-rigid, preferably transparenttube having a proximal end adapted to receive cardioplegia solution anda cardioplegia lumen which extends distally from the proximal end andterminates and communicates with an infusion port in the distal regionfor delivery of cardioplegia solution to the aorta. The occluder, whichhas a longitudinal center axis, is mounted on the distal region of thecannula. The occluder is expandable between a contracted condition andan expanded condition, wherein the occluder, when contracted, is closelyassociated with the outer surface of the cannula, while the occluderexpands upon activation to substantially occlude the aorta downstream ofthe infusion port. During use, the occluder isolates the ascending aortafrom the peripheral vasculature without substantial migration of theoccluder into the ascending aorta. Because of the substantially rigidcondition of the cannula, the balloon may have a relatively smallfootprint where it is coupled to the distal region of the cannulawithout substantial migration of the occluder into the ascending aorta.

The embodiment shown in FIG. 1 and FIG. 2 has three lumens within thecannula. Other embodiments may have more or fewer lumens. In someembodiments, certain lumens are separate, non-communicating channels. Incertain embodiments, the lumens are generally substantially cylindrical,semi-rigid and preferably transparent. In FIG. 1 and FIG. 2, acardioplegia lumen 4 is adapted to receive cardioplegia through itsproximal end and deliver it to an infusion port 5 at its distal end. Theinfusion port 5 is proximal to the occluder, so that when the occluderis in an expanded condition, cardioplegia infuses to a region upstreamfrom the occluded aorta. Another lumen 7 is adapted to receive fluidthrough its proximal end and deliver it to an inflation port 8 at thedistal end of the lumen where it terminates and is in fluidcommunication with the chamber 21 of the occluder. When the occluder iscontracted, it is closely associated with the cannula's outer surface15. When fluid is delivered to the chamber of the occluder through theinflation port, the occluder expands away from the cannula, as depictedin FIG. 1 and FIG. 2. In one embodiment, the pressurized fluid used tofill the chamber of the occluder is saline solution and in anotherembodiment, it is gas. In another embodiment, negative pressure may beapplied to the lumen 7 to contract a foam-filled balloon. An aspirationlumen 10 has a proximal end 12 adapted to couple to an aspirator, andextends distally from the proximal end and terminates and communicateswith the infusion port 5. In embodiments having an aspiration lumen, theinfusion port can alternately deliver cardioplegia solution or aspirateembolic debris and other unwanted material from the aorta.

FIG. 3 and FIG. 4 depict another embodiment of the cardioplegia occluder1 where the distal end 16 of the cannula 10 is open forming a cuttingblade lumen to receive the cutting blade 30. The distal end 31 of thecutting blade, which when exposed, protrudes beyond the in the distalend of the cannula, has a sharpened tip 32 adapted to cut through thewall of the aorta. The embodiment shown in FIG. 3 and FIG. 4 includes aretractable blade guard 33 which is inserted into the distal end 16 ofthe cannula. The blade guard 33 is adapted to slidably receive thecutting blade 30. During use, the blade guard moves when pressed againstthe aorta to allow the blade to cut through the wall of the aorta, andthen the blade guard repositions to prevent the blade from cutting. Inthe embodiment shown in FIG. 3 and FIG. 4, the proximal end 34 of thecutting blade guard is coupled to the distal end of a spring 35. Theproximal end of the spring 36 is coupled to the inner surface of thecannula. When the spring is at its compressed length, as depicted inFIG. 3, the retractable blade guard is retracted exposing the cuttingblade 31. When the spring is at its extended length, the retractableblade guard covers the sharpened tip of the cutting blade as depicted inFIG. 4.

The cardioplegia occluder depicted in FIG. 3 and FIG. 4 is placed on theaorta, upstream from the brachiocephalic artery. When pressure isapplied to the cardioplegia occluder, the surface of the aorta pushes onthe retractable blade guard, compressing the spring and exposing thesharpened tip of the cutting blade which cuts through the wall of theaorta to create an incision for introduction of the distal end of thecannula. The distal end of the cannula, with the occluder in acontracted condition, is introduced through the incision made by thecutting blade. Such an embodiment can be introduced through a site thatis a maximum of 18 French. During insertion, aspiration can be effectedthrough the aspiration lumen to remove intravascular debris or airintroduced into the aorta during incision. The curved distal end of thecannula is positioned at the desired location inside the aorta, and theoccluder is expanded by introducing fluid through the lumen 7. Once theoccluder is fully expanded, blocking the blood supply to the aorta inthe region distal to the occluder, cardioplegia solution may beintroduced through the infusion port to the region upstream from theoccluder to stop the heart. Cardiac surgery, may then be performed.Alternately, negative pressure can be applied to the proximal end of theaspiration lumen to remove cardioplegia and embolic debris from theaorta. In embodiments that do not include a cutting blade, the incisionis made manually, and the distal end of the cannula is inserted aspreviously described. Following surgery, the flow of cardioplegiasolution is stopped, negative pressure is applied to the lumen, theoccluder contracts, the cardioplegia occluder is removed through theincision initially created for its insertion and the incision is closed.

FIG. 5 shows another embodiment where a blood cannula 56 has a channel57 located laterally that is adapted to receive a cardioplegia occluder58. When the occluder 20 is expanded inside the aorta 41, cardioplegiasolution can be delivered upstream of the occluder through the infusionport 59. This embodiment is one example of an integrated configurationof a blood cannula and a cardioplegia occluder for use in a "one-stick"application, meaning that only one incision need be made.

Human anatomy including the rib cage with deployed cardioplegia occluderis depicted in FIG. 6. The cardioplegia occluder 1 is disposed through achest access port 40 and thereafter enters the aorta 41 behind thesternum 45 at a location 42 upstream from the brachiocephalic artery 43.The rib cage is depicted generally by numeral 44. The cardioplegiaoccluder 1 is shown deployed within the aorta 41. The concept of portaccess allows a surgeon to enter the aorta via a port for a minimallyinvasive approach. By accessing the aorta directly, the device isdeployed without the need for visual guidance, e.g., fluoroscopy,echocardiography. This device would obviate the need for a sternotomyprocedure which is generally associated with conventional coronaryartery bypass grafting surgery.

The cardioplegia occluder may be constructed to sit in either directiononce introduced in the aorta by varying the location of the infusionport. In one embodiment, depicted in FIG. 7, an L-shaped cardioplegiaoccluder 1 is constructed to sit inside the aorta with occluder 20downstream from the incision site 55, with the occluder 20 mounteddistal to, or downstream from, the infusion ports 5. The cardioplegiaoccluder optionally includes seating bumps 50 to enhance sealing withthe interior of the aorta. In another embodiment shown in FIG. 7A, aJ-shaped cardioplegia occluder 1 is constructed to sit inside the aorta41 so that the occluder 20 is mounted proximal to, but still downstreamfrom, the infusion port 5 which is located at the distal opening 14 ofthe cannula. These cardioplegia occluders can be inserted through apre-slit section of the aorta, or a cutting blade can be mounted on thedistal end of the cannula and advanced through the aortic wall.

An integrated, multiple component port access cardioplegia occluder isdepicted in FIG.8. The system includes a cutting blade 60 having apreshaped configuration 61, a sharp tip 62, and position limiters 63.The cannula 3 includes a suture plate 70, a kink-resistant shaft 71, anopening 72 to receive cardioplegia infusion solution into thecardioplegia lumen and a hemostasis valve 73. The balloon cannula 80includes an occluder 81, an inflation port 82 and a lumen 83 and isadapted to receive a filter mesh 500 through the lumen. The cannula 3 isadapted to receive the cutting blade 60 through the infusion port 72,and to receive the occlusion device 80 through the hemostasis valve 73.In use, a port access point or window is opened on the patient's chest.Tissue from the port to the aorta is dissected. The cutting blade andcannula are advanced through the aortic wall. A purse string suture(s)may be required to aid in wound closure and to secure the device. At thedesired location, the cutting blade is advanced through the aortic walland the cannula is pushed with the cutting blade. Once inside thevessel, the cannula is secured and the cutting blade is removed. At thispoint, the occluder (and any filter) may be advanced and expanded.Cardioplegia and other fluids may then be circulated through thecardioplegia lumen.

The distal end of the cannula may assume various designs to assist thesurgeon in positioning the cardioplegia occluder in the aorta. In oneembodiment, depicted in FIG. 9, a lumen 90 is adapted to receive thecutting blade 110. The cutting blade lumen 90 enters the distal regionof the cannula 3 at an angle. A substantially straight cutting blade 110is introduced into the lumen 90 so that the sharp tip 111 of the bladeprotrudes beyond the opening 91 at the distal end of the cutting bladelumen. In use, this embodiment allows for a single stick motion wherebythe cutting blade pierces the wall of the aorta creating an incision andthe distal end of the cannula, with the occluder in a collapsedcondition, is advanced through the incision. A flange 100 mounted on thecannula presses against the exterior surface of the aortic wallpreventing further movement of the cannula into the vessel at the pointwhere the cannula is positioned in the desired location within theaorta. The cutting blade is then retracted and the occluder 20 isexpanded to block the flow of arterial blood. An advantage of thisembodiment is that it has no moving parts other than the retractablecutting blade. In other embodiments, the cutting blade lumen extendsdistally from the proximal end of the cannula.

The embodiment depicted in FIG. 10 has a retractable cutting blade 112slidably inserted into a cutting blade lumen 92 within the distal end ofthe cannula 3. The proximal end 114 of the cutting blade is coupled to aspring 120 and to an activator line 130. The activator line can be madeof material such as wire. The proximal end of the spring is coupled to astop 121 formed inside the cutting blade lumen. When the activator line130 is pulled, the spring 120 compresses and the sharp tip 111 of thecutting blade 112 is retracted into the distal end of the cutting bladelumen 92 which then serves as a blade guard. When the activator line 130is released, the spring 120 expands and the sharp tip 111 of the deviceis exposed to allow incision into a vessel. The embodiment also includesinfusion ports 101 for introduction of cardioplegia solution upstreamfrom the occluder 20.

FIG. 10A shows another embodiment where the blade guard is a retractableobturator 140. In this embodiment, the distal end 114 of the cannula issharp, thus forming the cutting blade, and is used to create the initialincision into the aorta. The retractable obturator 140 is slidablyreceived through the cutting blade. In the embodiment of FIG. 10A, theretractable obturator is coupled on its proximal end to a spring 120 andto an activator line 130. The spring is coupled on its proximal end to astop 121 formed inside the cutting blade lumen. During use, theobturator can be moved by pulling on the activator line to expose thesharp distal end 114 of the cannula which is used to cut through thewall of the aorta. When the activator line is released, the obturatormoves back to prevent the blade from cutting.

FIG. 11 depicts a flange sleeve 105 adapted to receive the cannula. Insome embodiments, the flange sleeve is substantially cylindrical. Inother embodiments, the flange sleeve may have a different shape oncross-section such as square, rectangular, oblong or other shapes. Theflange sleeve has a sharpened distal end 116 adapted to cut through thewall of the aorta, an inner surface 108, an outer surface 109, aproximal end 117, a distal end and a longitudinal center axis. The lumen118 of the flange sleeve 106 runs along the longitudinal center axis andcommunicates with openings at the proximal 117 and distal 116 ends ofthe sleeve. This embodiment also includes a flange stop 107, with a topsurface 125, which faces the proximal end of the flange sleeve, and abottom surface 126, which faces the distal end 116 of the flange sleeve.The flange stop 107 is mounted on the flange sleeve. The perimeter ofthe flange stop can be substantially circular, or shaped so that aregion of the perimeter includes a protrusion or notch in the plane ofthe flange stop, where the protrusion or notch indicates the directionof the tip 128 of the cutting edge 116 of the flange sleeve. In theembodiment of FIG. 11, the portion of the flange sleeve distal to thebottom surface 126 of the flange stop 125 and proximal to the cuttingedge 116 at the distal end of the sleeve is of a length 119 that willposition the cutting edge 116 of the flange sleeve at a predetermineddepth inside the aorta when the bottom surface 126 of the flange stopcontacts the outer surface 46 of the aorta thus preventing furthermovement of the flange sleeve into the aorta. FIG. 11 shows the cannula3 retracted inside the lumen of the flange sleeve. When in the retractedstate, the occluder 20 is in a contracted condition. When in use, thecutting edge 116 of the flange sleeve is pressed into the outer surfaceof the wall of the aorta 46, while the cannula 3 is in the retractedstate and the occluder 20 is in a contracted condition. The cutting edge116 of the flange 105 is advanced into the aorta until the flange stop107 contacts the outer surface of the wall of the aorta 46. In the nextstep, as depicted in FIG. 12, the cannula 3 is advanced beyond thecutting edge 116 of the flange until the distal end of the cannula issituated at the predetermined position within the aorta 41. The occluder20 is then expanded to prevent blood flow downstream in the aorta. Inthis embodiment, the distal end of the cannula is semi-rigid andpreformed to assume a substantially curved condition when released fromthe flange. When retracted inside the flange, as depicted in FIG. 11A,the semi-rigid distal end of the cannula 3 generally conforms to theshape of the flange sleeve lumen which is straight.

In another embodiment, depicted in FIG. 13, the flange 105 includes aflange sleeve 106 with an inner surface 108, an outer surface 109, aproximal end 117, a distal end 129, and a longitudinal center axis. Thelumen 118 of the flange sleeve 106 runs along the longitudinal centeraxis and communicates with openings at the proximal 117 and distal 129ends of the sleeve. This embodiment also includes a substantially flatflange stop 107, with a top surface 125, which faces the proximal end ofthe flange sleeve, and a bottom surface 126 which is flush with thedistal end 129 of the flange sleeve. The bottom surface 126 of theflange stop is adapted to press against the outer surface 46 of theaorta. FIG. 13 also shows the cannula 3 partially retracted inside thelumen 118 of the flange sleeve. When in the retracted state, theoccluder 20, which is disposed about the distal region of the cannula 3,is in a contracted condition. In this embodiment, the distal end 145 ofthe cannula includes a cutting blade lumen having a retractable cuttingblade 146 with a sharpened cutting edge 147 at its distal end. Thecutting blade 146 slidably inserts inside the cutting blade lumen andprotrudes beyond the distal end 145 of the cannula 3. When in use, theflange 105 is positioned with the bottom surface 126 of the flange stop107 pressing against the outer surface of the wall 46 of the aorta andthe cannula 3 and cutting blade 146 are in the retracted state insidethe lumen 118 of the flange sleeve 106 proximal to the distal opening129 of the sleeve. The cannula 3 and the cutting blade 146 are pushedthrough the lumen 118 of the flange sleeve beyond the distal opening 129so that the sharpened cutting edge 147 of the cutting blade 146 cutsinto the wall of the aorta forming an incision as depicted in FIG. 13.Once the incision is formed, the cannula 3 is advanced beyond the distalopening 129 of the flange sleeve 106, as depicted in FIG. 13A, so thatthe distal end of the cannula and the occluder 20 are introduced intothe aorta 41 to the predetermined depth and position. In thisembodiment, the semi-rigid distal end of the cannula is preformed toassume a curved shape once it is released from the lumen of the flange.As the cannula is advanced beyond the distal opening 129 of the flangeinto the aorta, the cutting blade 146 slidably retracts within thecannula so that is does not protrude beyond the distal opening 146 ofthe cannula. Once the cutting blade has been deployed to create theinitial incision, it is desirable to retract it inside the cannula orotherwise guard the sharpened tip so that the sharp edge of the bladedoes not scrape or cut the inner surface 47 of the wall of the aortaopposite the incision site. The occluder 20 may then be expanded toocclude arterial flow downstream in the aorta.

In another embodiment, depicted in FIG. 14, the flange 105 includes aflange sleeve 106 with a proximal end 117, a distal end 129, and alongitudinal center axis. The lumen 118 of the flange sleeve 106 runsalong the longitudinal center axis and communicates with openings at theproximal 117 and distal 129 ends of the sleeve. This embodiment alsoincludes a substantially flat tear-away flange stop 150, with a topsurface 151, which faces the proximal end of the flange sleeve, and abottom surface 152, which is flush with the distal end 129 of the flangesleeve. The tear-away flange stop 150 is disposed about the outersurface of the flange sleeve 106 at the distal end 129 of the sleeve.The bottom surface 152 of the tear-away flange stop is adapted to pressagainst the outer surface 46 of the aorta to limit the initial insertiondepth into a vessel. FIG. 14 also shows the cannula 3 partiallyretracted inside the lumen 118 of the flange sleeve. When in theretracted state, the occluder 20 is in a contracted condition. A cuttingblade 160 is adapted to slidably insert inside a lumen within thecannula. In this embodiment, the distal end 161 of the cutting blade issharpened 161 to cut through the wall of the aorta. When in use, thecannula 3, with the sharpened cutting edge 161 of the canula insertiondevice 160 exposed, is advanced through the wall of the aorta until thebottom surface 152 of the tear-away flange stop 150 presses against theouter surface of the wall of the aorta. As depicted in FIG. 14A, thecutting blade 160 is then retracted within the distal end of the cannula3 as the tear-away flange is removed and the cannula is advanced intothe lumen of the aorta until the bottom surface 126 of the permanentflange stop 107 presses against the outer surface 46 of the wall of theaorta. By this process, the distal end of the cannula and the occluder20 are introduced into the aorta 41 to the desired depth and position.In this embodiment, the semi-rigid distal end of the cannula ispreformed to assume a curved shape once it is released from the lumen ofthe flange. The occluder 20 may then be expanded to occlude arterialflow downstream in the aorta.

As described previously, in certain embodiments, the distal region ofthe cannula may be preformed to a desired shape to allow the cannula tobe positioned at the desired depth and orientation within the aorta. Inother embodiments, the distal region of the cannula may be mechanicallyactivated by an occluder aligner to allow proper positioning of theoccluder within the aorta. FIG. 15 depicts an embodiment with one formof occluder aligner that includes a cannula 3 with an inner surface 170,an outer surface 171, a proximal end (not shown), a distal end 145 and alongitudinal center axis. The lumen 172 of the cannula runs along thelongitudinal center axis and communicates with openings at the proximaland distal 145 ends of the cannula. The cannula also includes a flangestop 107 disposed about the outer surface 171 of the distal region ofthe cannula. The occluder aligner of this embodiment includes a steeringwire 130 carried by the cannula, displaced from the center axis of thecannula and attached on a first end 131 in the distal region of thecannula, in the case of this embodiment, to the inner surface 170 of thedistal region. When in use, as depicted in FIG. 15 and FIG. 15A, thecardioplegia occluder 1 is advanced through an incision in the wall ofthe aorta 41 until the bottom surface 126 of the flange stop 107 pressesagainst the external surface of the wall 46 of the aorta. At this point,as shown in FIG. 15, the occluder 20 is in a contracted condition. Thesteering wire 130 is then manipulated, as depicted in FIG. 15A, to movethe distal end of the cannula into a curved condition, so that thedistal opening 145 of the cannula points downstream within the aorta 41.In one embodiment, the occluder is aligned by pulling on the steeringwire. In another embodiment, the steering wire is fabricated from amaterial that shortens upon application of a predetermined electricalinput. When this predetermined electrical input is applied to thesteering wire, the wire shortens by a predetermined length, pulling thedistal end of the cannula into the predetermined position. In anotherembodiment, a control circuit containing a memory storage devicecontrols the electrical input to be applied and the timing of theapplication and discontinuance of the electrical input, so that thechange in length of the wire may be programmed. Once the occluder 20 isproperly aligned within the aorta, the occluder may be expanded toocclude arterial flow downstream in the aorta.

FIG. 16 depicts another cannula that is mechanically activated tofacilitate proper positioning of the occluder within the aorta. Thisembodiment includes a cannula 3 with an inner surface 170, an outersurface 171 and a longitudinal axis. The cannula is divided into twosegments, a proximal portion 185 and a distal portion 186, flexiblycoupled to one another. In the embodiment shown in FIG. 16, the flexiblecoupling is a hinge 180. In the closed condition, as depicted in FIG.16, the distal end of the proximal portion 185 and the proximal end ofthe distal portion 186 align at a circumferential region 181, so thatthe cannula assumes a substantially cylindrical shape. In otherembodiments, the cannula on cross-section can be rectangular, square,oblong or other shapes. In the open condition, as depicted in FIG. 16A,the distal portion 186 rotates about the hinge so that the longitudinalaxis 188 of the distal portion 186 is about a 90° angle to thelongitudinal axis 187 of the proximal portion 185. In the closedcondition, the lumen 172 of the cannula runs along the longitudinalcenter axis and communicates with openings at the proximal and distal145 ends of the cannula. The cannula also includes a flange stop 107disposed about the outer surface 171 of the distal region of thecannula, and a cutting blade 160 which slidably inserts within the lumen172 of the cannula when the cannula is in the closed condition. When inuse, as depicted in FIG. 16, the cutting blade 160 protrudes beyond thedistal end 145 of the cannula 3 which is in the closed condition withthe occluder contracted. The presence of the cutting blade in the lumenof the cannula helps maintain the cannula in a closed position. Thesharp distal end 161 of the cutting blade 160 is advanced through thewall of the aorta 41 creating an incision, and the cannula 3 is advancedinto the aorta until the bottom surface 126 of the flange stop 107presses against the external surface of the wall 46 of the aorta. Thecanula insertion device is then removed causing the hinge to open asdepicted in FIG. 16A, and the cannula assumes the open condition withthe distal portion 186 of the cannula pointing downstream in the aorta.In some embodiments (not shown), the cannula opens with the assistanceof a spring-loaded hinge. The occluder 20 may then be expanded toocclude arterial flow downstream in the aorta. Cardioplegia solution maythen be introduced through the proximal portion 185 of the cannula fordelivery through the fluid port 189 upstream of the occluder.

FIG. 17 depicts an embodiment where the distal region of the cannula 3is tapered 210. The embodiment of FIG. 17 also shows, a curved region212, distal to the tapered region. In this embodiment, the taperedregion, on cross-section, as depicted in FIG. 18, is substantiallyelliptical. As also depicted in FIG. 18 from a top elevation, the longdiameter of the ellipse of the tapered region cross-section liesdirectly above the curved region 212 of the cannula. This embodimentalso includes a flange which is slidably received by the cannula. Theflange in this embodiment has a directional indicator. As can be seen inthe top elevation of FIG. 18, the flange assumes the shape of a polygon.In other embodiments, the flange can be other shapes such asrectangular, oblong, or triangular. The flange includes a hole 204 thatis substantially elliptical, having an inner circumference 202. The holeis placed off-axis from the center of the polygon. The long diameter ofthe elliptical hole is perpendicular to the directional edge 203 of thepolygon perimeter of the flange. The distance from the directional edge203 to the nearest point on the inner circumference of the hole 204 isgreater than the distance from the edge 201 opposite the directionaledge to the point on the inner circumference nearest that opposite edge.The inner circumference 202 of the hole in the flange is greater thanthe circumference of the outer surface 211 of the distal end of thetapered region 210 of the cannula, but less than the circumference ofthe outer surface 211 of the proximal end of the tapered region 210 ofthe cannula. The flange is disposed about the tapered region of thecannula. The distal end of the tapered region is adapted to slidablyinsert in the hole of the flange and the proximal portion of the taperedregion slidably inserts in the flange up to the location where thecircumference of the outer surface 211 of the tapered region of thecannula is substantially equal to the inner circumference 202 of thehole in the flange, at which location the flange is no longerfree-floating, and locks into position on the tapered region. Thetapered condition of the cannula assists in sealing the cannula to theflange. Since the hole 204 of the flange and the cross-section of thetapered region are both elliptical in shape, the flange will always beoriented in the same position on the cannula when it locks into place;that is, the directional edge 203 will always point toward the curvedregion 212 of the cannula, which assists the surgeon in knowing whichway the occluder is pointing in the aorta. In other embodiments, thetapered region 210 and the hole 204 of the flange may assume othershapes on cross-section, such as rectangular or triangular. In someembodiments, the directional edge is identified by a specific color. Theembodiment of FIG. 17 also includes marker bands 220 around the outersurface 211 of the curved region 212 of the cannula in the most proximaland most distal locations where the occluder 20 contacts the cannula.The marker bands are made of radiopaque material such as metal-polymericalloy so that the surgeon can identify the position of the occluder.

For the cardioplegia occluder to function properly, the occluder must beadapted to occlude aortas of varying diameters. Moreover, the internalsurface of the aorta may have varying surface features creatingadditional challenges to fashioning occluders that will conform to thetopography of the inner surface of the vessel and form a complete seal.The challenge of occluding aortas of varying diameter is furthercompounded in embodiments with fixed flanges. To overcome suchobstacles, in certain embodiments, the occluder is a balloon having afirst region of first expansion capacity and a second region of secondexpansion capacity where the first expansion capacity is greater thanthe second expansion capacity. During use, the second region expandspreferentially and to a greater extent than the first region. Theseembodiments can thus compensate for insertions where the distal end ofthe cannula does not lie directly in the center of the aorta and by thuscompensating creates effective sealing. In some embodiments, the varyingexpansion capacity is created by forming the first region from aflexible material of different thickness that the flexible material usedto create the second region. In other embodiments, the first region isof a different modulus (durometer) than the second region. In otherembodiments, the occluder is adapted to occlude aortas of varyingdiameters by asymmetrically mounting the balloon on the distal region ofthe cannula. The embodiment shown in FIG. 19, which demonstrates thislast case, has an occluder 20 that is a preformed asymmetric balloonwhere the "long" side 230 has less capacity to expand than does the"short" side 231. The flange 107, as described in previous embodiments,will hold the curved portion 212 of the cannula at a predetermineddistance below the region of the wall of the aorta closest to theflange. In aortas of varying diameters, the distance between the curvedportion of the cannula and the wall opposite the flange will necessarilyvary. To facilitate occlusion in these varying conditions, the shortside 231 has a greater capacity for expansion, as depicted in FIG. 19A,than does the long side 230, so that upon inflation by a common fluidsource, the short side 231 will preferentially expand over the long side230. FIG. 20 is a front elevation of the embodiment of FIG. 19A showinghow the short side 231 preferentially expands over the long side 230 toocclude aortas of smaller 240, intermediate 241, and larger 242diameters even though the flange 107 fixes the depth of the cannulawithin each vessel.

There are several methods to achieve varying capacities for expansion ingiven regions of the balloon occluder. Typically, it is desired toachieve a preferential expansion zone as depicted in FIG. 21 where aballoon occluder 20 is asymmetrically disposed about a cannula, and theoccluder has a region 251 that has a greater capacity to expand whencompared to another region 250. FIG. 22 is a lateral elevation of theembodiment of FIG. 21. These asymmetric balloons, which can befabricated from polyurethane, typically inflate to a more symmetricshape as depicted in FIG. 23, where varying balloon wall thickness isused to control expansion characteristics. A thin region 252 of theballoon will expand first, reaching a certain level of strain/elongation252', then a thicker region 253 will stretch to its expanded condition253'. The expanded balloon is symmetrically disposed about the cannula.

FIG. 24 depicts another embodiment where balloon materials withdiffering expansion capacities are used to create a balloon which isasymmetric upon expansion. In this embodiment, a region of soft material255, e.g., one of lower modulus and usually lower durometer, expandsmore freely 255' than does a region of harder material 254, e.g., one ofhigher modulus and usually higher durometer, which expands less freely254'.

It is also important that the occluder not prolapse at the locationswhere the occluder surface is not in contact with the inner surface ofthe aorta when the occluder is expanded. Such prolapse can cause theoccluder to not seal properly. Increasing thickness in these non-contactregions can reduce the risk of prolapse and can otherwise controloccluder length and shape. FIG. 25 depicts an embodiment where theballoon occluder has regions where the balloon material is thin 256 andsidewall regions where the balloon material is thick 257. When theballoon expands, the thin regions 256, which ultimately contact theinner wall of the aorta, expand more freely to their expanded condition256'. The thick sidewall regions 257, which do not contact the innersurface of the aorta and are thus at risk of prolapse, expand lessfreely to their expanded condition 257' and, due to their thickness, aremore robust. The overall average balloon length from location 260 tolocation 261 is reduced from the length that would otherwise result ifthe sidewalls were not made of thicker material. Thus, aprolapse-resistant balloon occluder with a small "footprint" (area ofcontact on the distal region of the catheter), can be fabricated. Thissmall footprint occluder, when used with the substantially rigid cannulaallows the occluder to isolate the ascending aorta from peripheralvasculature without substantial migration of the occluder into theascending aorta.

FIG. 26 depicts an embodiment of a cardioplegia occluder 1 where thesubstantially rigid cannula 3 includes three lumens 4, 10 and 7, aflange 107 and a spherical occluder 20. The infusion port 5 is shownproximal to the occluder. Certain embodiments of the cannula are made ofclear polycarbonate acrylic, ABS or stainless steel. In one embodiment,the region of the cannula proximal to the flange is made of clearpolycarbonate, acrylic or ABS, and the region of the cannula distal tothe flange is made of stainless steel. The plastic region and thestainless steel region are insert-molded at the junction. In thepreferred embodiment, (i) the length of the cannula from the proximalend to curved portion of the distal region is in the range of 5-10inches, most preferably 7.5 inches, (ii) the width of the distal regionfrom the beginning of the point of curvature to the distal end (distanceA in FIG. 26) is in the range of 0.25-0.75 inches, most preferably0.45-0.50 inches; and (iii) the distance between the flange and thedistal end (distance B in FIG. 26) is the range of 3/8 inch to 1.0 inch,and most preferably 3/4 inch. FIG. 27 is a front elevation of theembodiment of FIG. 26. FIG. 28 is a lateral cross-section of theembodiment of FIG. 27 shown through section line 28--28. Here, thepathways of the three lumens are depicted in greater detail. The lumen 7is shown communicating with the inflation port 8 which opens into thechamber of the occluder 20. The cardioplegia lumen 4 is showncommunicating with the infusion port 5 which opens into the region ofthe aorta upstream of the occluder. The aspiration lumen 10 alsocommunicates with the infusion port. FIG. 29 is a front elevation of thedistal region of the cannula 3 of the embodiment of FIG. 26 with theoccluder removed. In this figure, the closed distal end 14 of thecannula can be seen. FIG. 30 is a top elevation of the embodiment ofFIG. 29, showing the relative locations of the lumen 7 that is used toinflate/deflate the occluder, the cardioplegia lumen 4 and theaspiration lumen 10 as they enter the region of the cannula justproximal to the flange. FIG. 31 is a lateral view of the embodiment ofFIG. 29 with a partial cross-section of the curved region of thecannula. The occluder mounting zones 270 are shown on either side of thecross-section region. This view shows the relationship between theinfusion port 5, shown proximal to the occluder mounting zones, and theinflation port 8 which opens in the region between the occluder mountingzones and thus communicates with the chamber of the occluder. FIG. 32 isa bottom elevation of the embodiment of FIG. 29. FIG. 33 is a backelevation of the embodiment of FIG. 29, again showing the relativelocations of the infusion port 5 and the inflation port 8. FIG. 34 is alateral cross-section of the embodiment of FIG. 29 shown through thesection line 34--34.

FIG. 35 is an embodiment showing a self-expanding occluder 320 with ahollow Nitinol frame 300, a balloon seal 301 and a fluid-impermeablemembrane 302. The occluder is an annular-shaped balloon having an innercircumference and an outer surface and a flexible, fluid-impermeablemembrane bonded to the outer surface of the balloon and covering thearea circumscribed by the inner circumference of the annular balloon.FIG. 36 shows a cannula 3 with an occluder side port 310, a flange stop107 and a fluid port 311. FIG. 37 shows the self-expanding occluder 320,which has been inserted into the occluder side port 310 while in acollapsed condition after the distal region of the cannula has beeninserted into the aorta 41. Once properly positioned, the balloon seal301 is inflated through the hollow Nitinol frame 300 and the occluderexpands, occluding the vessel.

In some applications it is desirable to provide occluder constructionswith enhanced stability and/or increased expandability. FIG. 38 depictsan overlapping balloon occluder 321, fabricated with excess balloonmaterial, which allows the occluder to inflate to a larger size whilestretching and elongating to a lesser extent. A portion of the occluderin its expanded condition 321' is also shown. This embodiment may alsoinclude thicker regions of the balloon wall to control the inflationprofile.

In certain embodiments, the cannula is open at the distal end and thedistal end has a lumen where the occluder, when contracted, is stored asshown in FIG. 39. This figure depicts an expanding balloon occluder 322.Upon expansion, the balloon advances out of the distal end of thecannula. As the balloon is inflated, more balloon material is availableto expand, thus permitting occlusion of larger sized vessels once theballoon reaches its expanded condition 322'.

FIG. 40 and FIG. 41 depict a cannula with an open distal end for storageof a contracted balloon occluder 323. The balloon can be retracted upondeflation into the distal end 14 of the cannula 3 by pulling on anelastic line 330 which passes through the lumen of the cannula. Theelastic line 330 is coupled to the proximal end 331 of the balloon andthe distal end 332 of the balloon, so that when the balloon is fullyexpanded 323", the elastic line is fully stretched. Upon deflation, theelastic line contracts and the distal end 331 of the balloon movescloser to the proximal end 332 of the balloon. The deflated balloon 332may then be pulled into the distal end 14 of the cannula by pulling onthe elastic line 330. FIG. 41 depicts the balloon in its initialcontracted condition 323, a deflated condition 323' and a fully expandedcondition 323", where the elastic line is not shown.

In some applications it may be advantageous to cover the occluder with aprotective layer. FIG. 42 shows a balloon occluder 20 disposed about thedistal end of a cannula 3. The balloon 325 itself is made of an elasticmaterial and its outer surface is covered by a protective material 326.In some embodiments, the protective layer itself has elastic capacity.In other embodiments, the protective layer is internal to the balloon sothat the external surface of the protective layer is covered by theballoon material.

FIG. 43 depicts an embodiment where a funnel-shaped occluder 328 made ofelastic material is deployed through a side opening 340 of the cannula3. The funnel-shaped occluder 328 can occlude vessels of varying sizesdue to its shape.

Occluder aligners, which were described previously for manually aligningthe distal end of the cannula, can also be used to provide positionstability to expanding occluders. In some applications, an expandingoccluder will "rock" out of position during expansion if the distalregion of the cannula is not positioned along the center longitudinalaxis of the aorta. Certain embodiments therefore include cannulas withoccluder aligners of various designs to stabilize the position of theoccluder and distal cannula during occluder inflation. One embodimentincludes a longitudinally deformable region and an end sleeve whichslides relative to the distal end of the cannula and is coupled to thelongitudinally deformable region and to the occluder. During use, theoccluder expands and the end sleeve moves proximally, therebycompressing the longitudinally deformable region. FIG. 44 and 44Ademonstrate this embodiment, where the longitudinally deformable regionis a spring. FIG. 44 shows the distal region of the cardioplegiaoccluder 1 where the occluder 20 is in the collapsed condition. Thespring 400 is coiled about the distal region 401 of the cannula insidethe occluder chamber. The proximal end 402 of the spring is coupled tothe region of the cannula inside the occluder chamber just distal to theproximal end of the occluder 403. The end sleeve 404 is disposed aboutthe distal region of the cannula. The proximal end 405 of the end sleeveis coupled to the distal end of the spring 400. The end sleeve 400 iscoupled to the distal end of the occluder in a region 406 of the endsleeve just distal to the proximal end of the sleeve. The end sleeveincludes a seal 407 near the distal end of the sleeve adapted tosurround the distal region of the cannula 3 so that this distal cannularegion slidably inserts in the seal. The seal is adapted to preventfluid in the occluder chamber from escaping from the occluder. In thisembodiment, the occluder aligner includes an end stop 408 to prevent theend sleeve from sliding off the distal end of the cannula 3 during use.FIG. 44 also shows the location of the inflation port 8 inside theoccluder chamber. FIG. 44A shows the embodiment of FIG. 44 where theoccluder is in the expanded condition and the proximal end 405 of theend sleeve has moved along the distal region 401 of the cannula towardthe proximal end of the occluder 403 and the spring 400 has compressed.

FIG. 45 depicts an embodiment of a cardioplegia occluder 1 that includesan occluder aligner where the distal end of the end sleeve 404 of theoccluder aligner is a sharpened edge 420 that serves as a cutting blade.In use, the sharpened edge 420 creates the initial incision into theaorta and the cannula with the collapsed occluder is advanced into thelumen of the vessel. The occluder is expanded and the end sleeve 406slides proximally along the distal region 401 of the cannula retractingthe sharpened edge 420. In this embodiment, the longitudinallydeformable region of the occluder aligner is a flexible tube.

An occluder aligner with a steering sleeve slidably mounted on thecannula and coupled to a steering wire is depicted in FIG. 46. In thisembodiment, the steering sleeve 455 is disposed about the region of thecannula 3 proximal to the occluder 20, so that the cannula slidablyinserts in the steering sleeve. The distal end 453 of the steering wireis coupled to the inner surface of the distal region of the cannula inthe area where the occluder is coupled to the cannula. The steering wire454 is carried by the cannula and is displaced from the longitudinalcenter of the cannula. In some embodiments, the steering wire passesthrough a hole or slot in the cannula which is distal to the region ofthe cannula which is inserted into the vessel. The proximal end 455 ofthe steering wire is coupled to the steering sleeve. In use, duringoccluder expansion, the steering sleeve is manipulated to move thedistal end of the cannula. The steering sleeve can be moved along thecannula to elevate the distal end 450 as depicted in FIG. 46A and 46B.Steerable occluder aligners can be designed so that the distal end ofthe cannula is positioned at the center point of the largest vessel inwhich the cardioplegia occluder is to be used. When used in smallervessels, the tip will lie below the centerline and can be rotated up bypulling the steering sleeve distally.

As described previously, the cardioplegia occluder can be used inconjunction with other cardiopulmonary bypass equipment or other cardiacsurgical equipment including blood cannulas, filter cannulas anddiverters in various combinations as integrated systems or as separatelyinsertable devices. In certain embodiments, a "one-stick" method isused, meaning that one incision is made into the aorta to insert thevarious pieces of equipment in either their integrated or separatelyinsertable configurations. In other embodiments, "two-stick" or"three-stick" (two or three aortic incision) methods are used. In someembodiments, the occluder is mounted on the blood cannula instead of thecardioplegia cannula. TABLE 1, located at the end of the DetailedDescription section, is provided to assist in describing the variouscombinations.

FIG. 47 shows a two-stick embodiment with a blood cannula 600 (adaptedto receive separately insertable filter 500 through a channel thereof)inserted through one incision and a separate cardioplegia occluder 1inserted through a second incision. The filter is carried through sidechannel 601 of the blood cannula. Either a modular filter cannula asshown (see Ser. No. 08/853,165, filed May 8, 1997, incorporated hereinby reference, for more details) or an integral filter cannula (see Ser.Nos. 08/553,137, filed Nov. 7, 1995, now abandoned 08/580,223, filedDec. 28, 1995, now abandoned, 08/584,759, filed Jan. 11, 1996, nowabandoned 08/650,015, filed Apr. 30, 1996, now U.S. Pat. No. 5,723,099,and 08/852,727, filed Apr. 16, 1997, now U.S. Pat. No. 5,783,140, allincorporated herein by reference, for more details) can be used. In thisembodiment, a diverter 700 has been inserted in the region of the aorta41 where the aorta intersects the brachiocephalic artery 43, the leftsubclavian artery and the left common carotid artery. In all casesdescribed herein, whether one-, two- or three-stick and whether thevarious cannulas are integrated, separately insertable or certaincannulas are absent, the diverter may be (i) absent, (ii) inserted onlyfor the purpose of conducting the cardiac surgery, then removed at thecompletion of the surgery, or (iii) permanently installed in the aorta.The embodiment of FIG. 47 allows the cardioplegia occluder 1 to occludethe aorta distal to the infusion ports 5 where cardioplegia solution isintroduced to stop the heart. Downstream from the occluder 20, thefilter 500 traps embolic debris and other unwanted material that is abyproduct of the surgical activity. Downstream from the filter, theblood cannula supplies blood from a heart lung machine to the aorta forcirculation through the peripheral vasculature. The diverter 700, whichis permeable to blood, further inhibits embolic material and otherunwanted debris 800 from entering the cerebral vasculature by divertingit past the left common carotid artery and the brachiocephalic artery,which communicates with the right common carotid artery.

FIG. 47A shows an embodiment of a two-stick model where the cardioplegiaoccluder 1 is adapted to receive the filter 500 through a channelthereof, and the blood cannula 600 is inserted through a separateincision. A diverter is present, but as previously described, thediverter may be installed permanently, inserted only for the purpose ofsurgery or absent altogether in all one-stick, two-stick or three-stickmethods. Other embodiments of the two-stick method include (i) anintegrated cardioplegia occluder and blood cannula with a separatefilter, either inserted through a filter cannula or separately inserted,(ii) a separately inserted cardioplegia occluder, a separately insertedblood cannula and no filter cannula, (iii) a blood cannula occluder witha filter inserted through a channel in the cannula as shown in FIG. 49,or mounted on the cannula and a cardioplegia cannula inserted through aseparate incision, and (iv) a blood cannula occluder and a cardioplegiaoccluder inserted through a separate incision and no filter.

FIG. 48 depicts a three-stick method with a separately insertedcardioplegia occluder 1, a separately inserted filter cannula 501 and aseparately inserted blood cannula 600. In this embodiment, the diverter702 is present, but any of the three diverter configurations could beutilized. In another embodiment, the filter is separately insertedwithout the use of a filter cannula, as shown in FIG. 50.

In other embodiments, a one-stick method is used. In one embodiment,depicted in FIG. 51, the cardioplegia occluder and blood cannula areintegrated 900, and the filter separately inserted through a channel inthe cannula. In other embodiments, the filter may be mounted on thecannula or absent. Again, each combination has three possible diverterconfigurations.

In certain embodiments of the one-, two- and three-stick methodsdescribed above, the cardioplegia occluder may be replaced by a separateballoon cannula and a cardioplegia cannula. In such cases, the ballooncannula and the cardioplegia cannula can be separately inserted or canbe integrated with one another or each integrated with the filtercannula or the blood cannula.

    ______________________________________                                        Cardioplegia      Blood                                                       occluder       Filter                                                                           Cannula                                                     (CPO)          (F)                                                                                 (BC)  Description                                        ______________________________________                                        ONE-STICK*                                                                    (1a) +         +      +     Integrated CPO/BC; filter                                                      separately inserted through cannula                                           FIG. 51) or mounted on cannula                   (lb)     +       -     +     Integrated CPO/BC                                TWO-STICK*                                                                    (2a) +         +      +     Filter inserted through                                                       CPO (FIG. 47A) or                                                             mounted on CPO                                    2b    +        +       +     Filter inserted through BC                                                   channel (FIG. 47) or mounted on                                                   BC                                            2c   +         +      +            Integrated CPO/BC; filter                                              through filter cannula                                                        or separately                                                                                inserted                           2d    +        -        +       Separately inserted CPO and BC                2e   CP        +      BCO             Occluder on BC; fllter inserted                                      through blood cannula                                                                    occluder (BCO) (FIG. 49) or                                       mounted on BCO, cardioplegia                                                                       (CP) cannula separately                                  inserted                                          2f   CP         -      BCO          Occluder on BC, CP cannula                                            separateiy inserted                               THREE-STICK*                                                                  (3a) +         +      +     Filter separately inserted                                                     through filter cannula                                                       or without cannula                                ______________________________________                                         *It is to be noted that each combination listed has three possible            variants as to a diverter. The diverter may be (i) absent, (ii) inserted      only for the purpose of conducting the cardiac surgery, then removed at       the completion of the surgery, or (iii) permanently installed in the          aorta.                                                                   

While particular devices and methods have been described for using thecardioplegia occluder, once this description is known, it will beapparent to those of ordinary skill in the art that other embodimentsand alternative steps are also possible without departing from thespirit and scope of the invention. Moreover, it will be apparent thatcertain features of each embodiment as well as features disclosed ineach reference incorporated herein, can be used in combination withdevices illustrated in other embodiments. Accordingly, the abovedescription should be construed as illustrative, and not in a limitingsense, the scope of the invention being defined by the following claims.

We claim:
 1. A method for administering cardioplegia, comprising thesteps of:providing a substantially rigid cannula having proximal anddistal ends, and a proximal and a distal region, a balloon occludermounted on the distal region and communicating with an inflation lumenextending proximal from the occluder, a port on the cannula proximal theballoon, the port communicating with first and second lumens whichextend proximally from the port; making an incision in the aorta;inserting the distal end of the cannula and the occluder through theincision in the aorta; expanding the occluder to occlude the aortadownstream of the infusion port; and infusing cardioplegia solutionthrough the port, wherein the occluder isolates the ascending aorta fromperipheral circulation without substantial migration within theascending aorta.
 2. The method of claim 1, wherein the first and secondlumens merge and communicate proximal the port.
 3. A method foradministering cardioplegia to the aorta during cardiac surgery,comprising the steps of:providing a substantially rigid cannula having adistal region with an outer surface, a distal end adapted to enter theaorta, a proximal end adapted to receive cardioplegia solution, acardioplegia lumen which extends distally from the proximal end andterminates and communicates with an in fusion port in said distal regionfor delivery of cardioplegia solution to the aorta, and an occludermounted on the distal region of the cannula, said occluder expandablebetween a contracted condition and an expanded condition, and whereinthe occluder, when expanded, substantially occludes the aorta downstreamof the infusion port; making an incision in the aorta; inserting thedistal end of the cannula and the occluder through the incision in theaorta; expanding the occluder to occlude the aorta; and infusioncardioplegia solution through the infusion port to arrest the heart,wherein the occluder isolates the ascending aorta from peripheralcirculation without substantial migration within the ascending aorta. 4.The method of claim 3, wherein said cannula carries a cutting blade, andwherein the step of making an incision in the aorta is performed by thecutting blade.
 5. The method of claim 3, wherein the occluder, whencontracted, is adapted to conform to the outer surface of the cannula.6. The method of claim 3, wherein the infusion port is proximal theoccluder.
 7. The method of claim 3, wherein the occluder is a balloonoccluder.
 8. The method of claim 3, wherein the cannula furthercomprises an arterial return lumen which extends distally from theproximal end of the cannula and terminates and communicates with asecond port.
 9. The method of claim 8, wherein the second port is distalthe occluder.
 10. The method of claim 3, further comprising the step ofplacing the patient on cardiopulmonary bypass.
 11. The method of claim3, further comprising the steps of contracting the occluder and removingthe cannula and the occluder from the aorta.
 12. The method of claim 3,wherein the cannula further comprises a second lumen which extendsdistally from the proximal end and terminates and communicates with theinfusion port.
 13. The method of claim 12, further comprising the stepof aspirating fluid from the aorta by applying negative pressure to thesecond lumen.
 14. The method of claim 3, further comprising the steps ofperforming a coronary artery bypass graft procedure.
 15. The method ofclaim 3, wherein the distal region of the cannula is L-shaped.
 16. Themethod of claim 3, wherein the distal region of the cannula is bent atan angle of approximately 90 degrees.
 17. The method of claim 3, whereinthe distal region of the cannula includes a curved region.
 18. Themethod of claim 17, wherein the occluder is a balloon occluder, andwherein the balloon covers a portion of the curved region.
 19. Themethod of claim 7, wherein the cannula further comprises an inflationlumen which extends distally from the proximal end of the cannula andterminates and communicates with an interior of the balloon.
 20. Themethod of claim 3, wherein the distal region of the cannula is tapered.21. The method of claim 3, wherein the occluder expands to assume agenerally spherical shape.
 22. The method of claim 7, wherein saidballoon occluder is made of an elastic material.
 23. The method of claim7, wherein the balloon occluder further comprises a protective materialcovering the outer surface of said balloon.
 24. The method of claim 3,wherein the occluder is a foam-filled, self-expanding balloon.
 25. Themethod of claim 3, wherein the canula further comprises a suture flange.26. The method of claim 25, wherein said flange is slideably mounted onthe cannula.
 27. The method of claim 25, wherein said flange furtherincludes a directional indicator to indicate the direction of the distalend of the cannula.
 28. The method of claim 4, wherein the cutting bladefurther includes a blade guard.
 29. The method of claim 28, wherein theblade guard slideably receives the cutting blade and moves when pressedagainst the aorta to allow the blade to cut through the wall of theaorta and then repositions to prevent the blade from further cutting.30. The method of claim 28, wherein said blade guard is a retractableobturator which is slideably received through said cutting blade andmoves when pressed against the aorta to allow the blade to cut throughthe wall of the aorta and then repositions to prevent the blade fromfurther cutting.
 31. The method of claim 3, wherein a portion of thecannula extending beyond the infusion port is solid.